I have a Cx4 Storm in .40 and it's only accurate up to about 50m. In my opinion a red dot 1x sight such as an eotech is best for this short range carbine.
I have a non restricted in 9mm. I was going to put a scope on it, but the "ears" ie iron sight hoods make it a pain. I found the Eotech doesn't fit well due to the left side charging handle. I put my M21 with quick release and the bullet reticle (ie Eotech like) on it. This was the optic from my Tavor. Works very well. A buddy put one of the Bushnell holographic sights on his (Eotech without the extra protection). It seems to be thinner and able to work with the Storm.


















































